Die Infektion mit dem Hepatitis C Virus (HCV) gilt als eine der Hauptursachen für chronische Hepatitiden und führt häufig zu Leberzirrhose und Leberkarzinom. Weltweit sind etwa 200 Millionen Menschen mit diesem Virus infiziert. Die aktuelle Behandlung der Hepatitis C mit Ribavirin und Interferon-alpha ist langwierig, beeinträchtigt durch Nebenwirkungen und führt nur bei einem Teil der Patienten zur Heilung. Aus diesem Grund ist die Entwicklung eines präventiv oder therapeutisch einsetzbaren Impfstoffes gegen HCV-Infektionen sehr wünschenswert. Das hoch attenuierte und in seiner Vermehrungsfähigkeit extrem eingeschränkte modifizierte Vakziniavirus Ankara (MVA) gehört zu den viel versprechendsten Kandidaten für die Entwicklung neuartiger rekombinanter Virusimpfstoffe. Im Rahmen dieser Arbeit sollten erste rekombinante MVA-HCV-Viren auf ihre Eignung als Impfstoffe untersucht werden. Als Zielantigene dienten wichtige virale Strukturproteine, darunter das unter den HCV-Genotypen hoch konservierte Nukleokapsidprotein Core, sowie das Nichtstrukturprotein NS3, welches als regulatorisches Virusprotein im HCV-Replikationszyklus eine wichtige Rolle spielt, untersucht werden. Hierfür wurden die rekombinanten MVA-Viren MVA-P7.5-HCV core (MVA-core) und MVA P7.5-HCV-1-830 (MVA-1-830) eingesetzt, welche für die HCV-Strukturproteine codierende Gensequenzen unter der Kontrolle des Vakziniavirus-spezifischen Promotors P7.5 exprimieren. Zusätzlich wurde ein weiteres rekombinantes Virus MVA-P7.5-HCV-NS3 (MVA-NS3) konstruiert, welches die Gensequenz für das HCV-Nichtstrukturprotein NS3 trägt. Alle Vektorviren erwiesen sich in in vitro Experimenten als genetisch stabil, erlaubten die Produktion der rekombinanten HCV-Antigene in infizierten Zielzellen und waren somit geeignet für in vivo Untersuchungen im Mausmodell. Da HCV-spezifischen CD8+-T-Zellantworten eine wichtige Rolle bei der Ausheilung einer Hepatitis C zugeschrieben wird, sollte insbesondere die Anregung dieser Immunantworten untersucht werden. Dabei zeigte sich, dass bereits eine einmalige Immunisierung mit MVA-core, MVA-1-830 oder MVA-NS3 ausreichend ist, um HCV-spezifische CD8+-T-Zellantworten zu induzieren. Diese CD8+-T-Lymphozyten konnten ex vivo in Epitop-spezifischer Weise zur Interferon-gamma-Synthese stimuliert werden, ließen sich Antigen-spezifisch in vitro expandieren und waren in der Lage, HCV-spezifische Zielzellen zu erkennen und zu lysieren. Zudem konnte eine Steigerung der Immunantworten durch Mehrfachapplikation der MVA-Vakzinen erzielt werden. Im Folgenden gelang es, die HCV-spezifischen CD8+-T-Zellantworten durch kombinierte Applikation der MVA-Vakzinen mit anderen rekombinanten Virusimpfstoffen wie Semliki-Forest-Viren oder Adenoviren, sowie mit Plasmid-DNA weiter zu verstärken. Solche Impfstrategien sind viel versprechend, da sich die gemeinsame Komponente der eingesetzten, unterschiedlichen Vektorvakzinen auf die rekombinanten Antigene beschränkt und eine starke Immunreaktion auf diese Antigene angeregt wird. Die in dieser Arbeit gewonnenen Erkenntnisse erlauben die Schlussfolgerung, dass rekombinante MVA-Vektoren, die HCV-spezifische Antigene produzieren, dafür geeignet sind, um nach Impfapplikation HCV-spezifische zelluläre Immunantworten zu induzieren. Die im Tiermodell erarbeiteten, optimierten Immunisierungsstrategien liefern eine erste Grundlage für weitere Immunisierungsexperimente in Primatenmodellen und zur Planung erster klinischer Studien im Menschen. / Infections with hepatitis C virus (HCV) are considered as one of the main causes for chronic hepatitis and often lead to liver cirrhosis and hepatocellular carcinoma. About 200 million people worldwide are chronically infected with this virus. The current antiviral therapy relying on ribavirin and interferon-alpha is time consuming, often impaired by side effects and leads to resolution of the disease in only a part of the patients. For this reason, the development of a prophylactic or therapeutic vaccine against HCV infections is very desirable. The highly attenuated and replication deficient modified vaccinia virus Ankara (MVA) is one of the most promising candidates for development of new generation virus vaccines. Purpose of this work was to evaluate first recombinant MVA HCV viruses for their suitability as vaccines against hepatitis C. HCV structural proteins, amongst them the highly conserved core protein, as well as the non-structural protein NS3, which plays a key regulatory role in the HCV replication cycle, served as target antigens for MVA vaccine development. First, we investigated recombinant MVA viruses MVA-P7.5-HCV-core (MVA-core) and MVA-P7.5-HCV-1-830 (MVA-1-830), which express the coding gene sequences for HCV structural proteins under control of the vaccinia virus specific promoter P7.5. Second, we constructed and characterized a recombinant virus MVA-P7.5-HCV-NS3 (MVA-NS3) that carries the gene sequence for the HCV non-structural protein NS3. As demonstrated by in vitro experiments, all vector viruses were genetically stable, permitted the production of recombinant HCV antigens in infected target cells and were thus suitable for in vivo experiments using mouse models. Since HCV specific CD8+ T cell responses are considered important in hepatitis C virus clearance, special emphasis was given to the analysis of induction of this kind of immune response. When tested in first vaccination experiments, already a single immunization with MVA-core, MVA-1-830 or MVA-NS3 was sufficient to induce HCV specific CD8+ T cell responses. These CD8+ T lymphocytes could be stimulated ex vivo in an epitope specific manner, resulting in interferon-gamma production, could be further expanded in vitro and were able to recognize and lyse HCV specific target cells. Additionally, multiple applications of the MVA vaccines resulted in an increase of these cellular immune responses. In a final series of experiments, the possibility to further amplify HCV specific CD8+ T cell responses could be demonstrated by using combined applications of MVA with other experimental gene transfer vaccines based on Semliki Forest virus, adenovirus or plasmid DNA. Overall, the results of this work clearly suggest that recombinant MVA vectors delivering HCV specific antigens, are suitable candidate vaccines for induction of HCV specific cellular immune responses upon immunization. Importantly, the definition of optimized immunization strategies offers a rational basis for further immunization studies in primate models and for the conception of first clinical studies in humans.

Ph.D. thesis, Faculty of Health Sciences, University of the Witwatersrand, 2009

Thesis is submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Science (Biochemistry), University of the Witwatersrand, Johannesburg, 1992 / An investigation has been made into aspects of the expression of oncogenes in normally dividing cells and in hepatoceilular carcinoma (Hee). HOC occurs commonly in Southern Africs, and thf1aetiology ·ofthis tumour lsaseccieted with hepatitis a virus (HBV) infection. c·erbA, c..mva and e-tos but not c~Ha..res mANA were elevatad in tumours and adjacent hepatic tissue from the same petiEJ;htswhen compared to normal liver. Amounts of Fos and MYQ prot~in in the liver tumour specimens were else raised. The"e was some correlation between the patients' serum a..fetoproteirt concentretlons, histological features of tumour differentiatic)t"l, c..mvc and c40s r.ixpression. expression of e-tas and c..myc has been reportec to be elevated after stimulation of cells to alvlde, ,'1$ occurs during liver r19ganeration. This was corroborated by the findin~ that c-mvc, c·fo~· and c-jun mRNA concentratlona "Jere increased it"! cultured 3T6 mouse fibroblasts following treatment with alkaline medium aa a mitogenlo stimulus. The time course of the expression of these oncogenes was similar to that reported after gro\l'l/th factor sttmulation, The H[~V X..gene ma\' be responsible for increased oncogene expression it' YCC as a result of its documented trans activating properties. This vi!'a~ gene is unusual in that it has a codon preferanc";which is similar to that of eukarvotic ceU genes. Also HBV may ha'V& evolved from ti similar ancestral virus to that giving rise to retroviruses. These ideas suggest that the HBV X·gene is a viral oncogene derived from a host homologue. Low stringency Northern brot hybridisation using a X-gene probe denlonstrated a murine transcrlpt in heart and thymus. Attempts to isolate the sequence from mouse heart and thymus eDNA libraries ware unsuccessful despite ext,~n$jve screening with sensitive probes (SP6 palymerfjsa and peR fab(':.lUed X~gen~~fragments). Conserved X~gene \ . I sequences were also used fot the desigr:Jof primers in .~.peR bas£'d method " . II aimed at isolating a mammalian sequence. No sinnificant sequsnce \\ homology was found bet\lveen the HBVI\X..gene and Ol\A ampllfle'd from \1 l! gen(llmic and eDNA I1br'srytemplate sou~\pes.The peR preducts ttppeared to have been artef.,ots of arnplWaation. ~~n'IJreto detect the hQrtll.)logous gene may have resu~ted from poo' complS,JIlentarity between the VIral ant! \\ mammalian secuencec, 1\ \\ Non..~pecific amplification is commonly enct~unter&d when u$1110 PCli'. A qtJick asvmmatrlc re·ampW~catj(ii1 method I,?ssed on eXUOSilin of an " interm.uly' hybrfdising X·gelllapfimar we! davisQ\j to confirm FICRprOdu(,ts. The l"n1ithodwas specific irlthat "ver~ single bas~ mlsmatohe$ betwsen the internal primer and tem1>late re;.,ultad in fatJut~ of dete(;tabla \tUim$f extension. / GR 2016

Infection with hepatitis C virus (HCV) can cause liver damage known as fibrosis, which often leads to liver disease and hepatocellular carcinoma. The impairment of circulating, bulk (non-specific and specific) CD8+ T cells within HCV-infection, characterized by an altered phenotype and the increased expression of pro-apoptotic genes, is observed when compared to uninfected controls. The relationship between bulk CD8+ T cell function and the extent of liver damage has not been demonstrated. In this study, widespread immune alterations were observed in untreated HCV infection with advanced liver fibrosis. Untreated HCV-infected individuals with advanced fibrosis possessed a significantly decreased proportion of naïve CD8+ T cells and an increased proportion of late effector memory CD8+ T cells compared to uninfected controls. Upon T cell receptor (TCR) stimulation, these individuals also had an increased intracellular IFN-γ expression for four CD8+ T cell subsets, a decreased CD107a expression for central memory CD8+ T cells, and a decreased perforin induction for naïve and central memory CD8+ T cells. These immune alterations did not reverse 24 weeks after viral cure. This study indicates there is a relationship between the differentiation and function of bulk CD8+ T cells and the extent of liver damage within HCV infection.

Chan Ming Lok. / Thesis submitted in: December 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 93-108). / Abstracts in English and Chinese. / Ackowledgments --- p.i / Abstract in English --- p.ii / Abstract in Chinese --- p.iii / List of Abbreviations --- p.iv / List of Tables --- p.v / List of Figures --- p.vi / Chapter Chapter 1 --- Introduction and Objectives / Chapter 1.1 --- Hepatocellular Carcinoma --- p.1 / Chapter 1.1.1 --- Epidemiology --- p.1 / Chapter 1.1.2 --- Geographical Distribution --- p.1 / Chapter 1.1.3 --- Sex and Age --- p.1 / Chapter 1.1.4 --- Etiology --- p.2 / Chapter 1.1.5 --- Molecular Basis of HCC --- p.3 / Chapter 1.1.6 --- Situation in China and Hong Kong --- p.4 / Chapter 1.2 --- The Hepatitis B Virus --- p.5 / Chapter 1.2.1 --- Morphology --- p.5 / Chapter 1.2.2 --- Structure of the HBV Genome --- p.6 / Chapter 1.2.3 --- Functional Domains of the HBV Genome --- p.9 / Chapter 1.2.4 --- Pathogenesis of HBV Infection --- p.11 / Chapter 1.3 --- HBx --- p.12 / Chapter 1.3.1 --- The HBV x Gene --- p.12 / Chapter 1.3.2 --- The HBX Protein --- p.13 / Chapter 1.3.3 --- "Preferential HBX Expression in Sera, Hepatitis, Cirrhosis and HCC" --- p.13 / Chapter 1.3.4 --- Cellular Localization of HBX --- p.14 / Chapter 1.3.5 --- Animal Studies --- p.15 / Chapter 1.3.6 --- Functional Studies on HBX --- p.15 / Chapter 1.3.7 --- Variations in the HBx Gene --- p.21 / Chapter 1.4 --- Objectives of this Study --- p.24 / Chapter Chapter 2 --- Methods and Materials Methods / Chapter 2.1 --- Paraffin Embedding of Patient Tissue Samples --- p.26 / Chapter 2.1.1 --- Tissue Processing --- p.26 / Chapter 2.1.2 --- Paraffin Embedding of Tissue Samples --- p.26 / Chapter 2.2 --- Sectioning of Paraffin Embedded Tissue Sections --- p.26 / Chapter 2.3 --- Immunohistochemical Staining of Paraffin Embedded Tissue Sections --- p.26 / Chapter 2.3.1 --- Dewaxing of Paraffin-Embedded Tissue Sections --- p.26 / Chapter 2.3.2 --- Rehydration of Tissue Sections --- p.27 / Chapter 2.3.3 --- Antigen Retrieval --- p.27 / Chapter 2.3.4 --- Quenching of Endogenous Hydrogen Peroxidase --- p.27 / Chapter 2.3.5 --- Blocking of Endogenous Biotin and Non-Specific Protein Binding --- p.27 / Chapter 2.3.6 --- Antibody Incubation and Color Development --- p.27 / Chapter 2.3.7 --- Counterstaining and Coverslip Mounting --- p.28 / Chapter 2.3.8 --- Interpretation of Immunostaining Results --- p.28 / Chapter 2.4 --- DNA Extraction from HCC Tissues --- p.28 / Chapter 2.4.1 --- Sectioning of Frozen HCC Specimens --- p.28 / Chapter 2.4.2 --- Proteinase K Digestion and Phenol Chloroform Extraction --- p.29 / Chapter 2.4.3 --- Ethanol Precipitation and Re-suspension in Tris-EDTA (TE) Buffer --- p.29 / Chapter 2.5 --- Quantitation and Purity Check of Extracted DNA --- p.29 / Chapter 2.6 --- Quality Check for Extracted Genomic DNA --- p.30 / Chapter 2.6.1 --- Agarose Gel Electrophoresis --- p.30 / Chapter 2.6.2 --- Polymerase Chain Reaction (PCR) of the β-globin Gene --- p.30 / Chapter 2.6.3 --- Analysis of PCR Fragments by Agarose Gel Electrophoresis --- p.30 / Chapter 2.7 --- Polymerase Chain Reaction Amplification of HBs and HBx Genes of the Hepatitis B Virus --- p.31 / Chapter 2.8 --- Southern Blot of HBx PCR Fragments --- p.31 / Chapter 2.8.1 --- Immobilization of DNA onto a Positively Charged Nylon Membrane and Pre-hybridization --- p.31 / Chapter 2.8.2 --- Radio-labeling of an HBV Probe --- p.32 / Chapter 2.8.3 --- Hybridization of a 32P-labeled HBV Probe and Film Exposure --- p.32 / Chapter 2.9 --- Cloning of PCR Fragments into pGEM®-T Vector for Sequencing --- p.33 / Chapter 2.9.1 --- Gel Extraction and Purification --- p.33 / Chapter 2.9.2 --- Ligation --- p.33 / Chapter 2.10 --- Transformation of Competent DH5a cells --- p.34 / Chapter 2.10.1 --- Preparation of Competent DH5α Using Calcium Chloride --- p.34 / Chapter 2.10.2 --- Heat Shock of Competent DH5α Cells --- p.34 / Chapter 2.10.3 --- Plating of Transformed Cells onto LB Agar Plates --- p.34 / Chapter 2.10.4 --- Screening of Transformants for Inserts --- p.35 / Chapter 2.11 --- Miniprep of Plasmid DNA --- p.35 / Chapter 2.11.1 --- Inoculation of Bacterial Clones --- p.35 / Chapter 2.11.2 --- DNA Extraction by Alkaline Lysis and Phenol/Chloroform --- p.35 / Chapter 2.11.3 --- Ethanol Precipitation and Re-suspension in TE Buffer --- p.35 / Chapter 2.11.4 --- Confirmation of Positive Clones --- p.36 / Chapter 2.12 --- Sequencing of pGEM®-T Cloned HBx PCR Fragments --- p.36 / Chapter 2.13 --- Construction of the HBx-GFP Plasmid --- p.36 / Chapter 2.13.1 --- PCR Amplification of HBx Gene Inserts --- p.36 / Chapter 2.13.2 --- Confirmation of HBx Insert Sequence by DNA Sequencing --- p.37 / Chapter 2.13.3 --- Restriction Digest of HBx-pGEM®-T Plasmids to Obtain HBx Inserts --- p.37 / Chapter 2.13.4 --- Restriction Digest of pEGFP-Nl Cloning Vector for Cloning --- p.37 / Chapter 2.13.5 --- Ligation of HBx Inserts into the pEGFP Cloning Vector --- p.37 / Chapter 2.14 --- Large Scale Plasmid DNA Preparation --- p.38 / Chapter 2.15 --- Cell Culture --- p.39 / Chapter 2.16 --- Transfection using LipofectAminéёØ --- p.39 / Chapter 2.16.1 --- Seeding of Cells for Coverslip Growth --- p.39 / Chapter 2.16.2 --- Transfection using LipofecAminéёØ --- p.39 / Chapter 2.17 --- Cell Fixation and DAPI Staining Materials --- p.40 / Chapter 2.18 --- Chemicals --- p.41 / Chapter 2.19 --- Antibodies --- p.41 / Chapter 2.20 --- "Formalin-fixed, Paraffin Embedded Tissues of HCC Tissues from Xiamen" --- p.41 / Chapter 2.21 --- Frozen Liver Tissues --- p.41 / Chapter 2.22 --- PCR Reagents --- p.43 / Chapter 2.23 --- Primers --- p.43 / Chapter 2.24 --- Plasmid --- p.43 / Chapter 2.25 --- Enzymes --- p.43 / Chapter 2.26 --- Ligation Reagents --- p.43 / Chapter 2.27 --- Cloning Vectors --- p.45 / Chapter 2.28 --- Competent Cell --- p.45 / Chapter 2.29 --- Hela and HepG2 Cell Line --- p.45 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Hepatitis B Virus Status of HCC Patients from Hong Kong and Xiamen --- p.46 / Chapter 3.2 --- Immunohistochemical Studies of the HBx Protein in Hong Kong and Xiamen HCC --- p.46 / Chapter 3.2.1 --- Cross Reaction of Anti-99 with Cytokeratin 18 (CK18) --- p.46 / Chapter 3.2.2 --- HBx Expression in HCC Patient Tissue Samples from Hong Kong --- p.50 / Chapter 3.2.3 --- HBxAg Staining in HCC Tissue Samples from Xiamen --- p.50 / Chapter 3.3 --- Agarose Gel Electrophoresis of DNA Extracted from Frozen Liver Tissues --- p.50 / Chapter 3.4 --- PCR Amplification of the β-globin Gene --- p.55 / Chapter 3.5 --- PCR Amplification of the HBs Gene from Liver Samples of HCC Patients from Hong Kong --- p.55 / Chapter 3.6 --- PCR Amplification of the HBx Gene from Liver Samples of HCC Patients from Hong Kong --- p.55 / Chapter 3.7 --- Amplification of the HBx Gene from Serum Samples of Chronic Hepatitis B Virus from Hong Kong Using Nested PCR --- p.61 / Chapter 3.8 --- Southern Blot of HBx PCR Fragments --- p.61 / Chapter 3.9 --- Cloning and Sequencing of the HBx Gene in HCC and Chronic Hepatitis B Patient Samples from Hong Kong --- p.61 / Chapter 3.10 --- Expression Pattern of Wild-type HBx-GFP Fusion Protein in Transiently Transfected HeLa and HepG2 Cells --- p.73 / Chapter 3.11 --- Expression Patterns of HBx-GFP with and without Mutations at Codons 130 and 131 in HeLa and HepG2 Cell Line --- p.78 / Chapter 3.12 --- Growth Kinetics of HeLa Cells Transfected with GFP and Wild-type HBx-GFP with and without Mutations in Codons 130 and131 --- p.81 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- HBxAg Expression in Tumorous and Surrounding Non-tumorous Tissues --- p.83 / Chapter 4.2 --- "Detection of the HBx Gene in Sera, Non-tumorous and Tumorous Tissues" --- p.84 / Chapter 4.3 --- HBx Gene Mutations in Chronic Hepatitis and HCC --- p.85 / Chapter 4.3.1 --- Codon 127 (HBV nt 1752-1754) --- p.85 / Chapter 4.3.2 --- Codons 130 and 131 (HBV nt 1761-1766) --- p.86 / Chapter 4.3.3 --- Lack of Correlation between HBx Gene Mutations and Lack of HBxAg Expression --- p.87 / Chapter 4.4 --- Cellular Localization of HBxAg in Transiently Transfected Cells Lines --- p.88 / Chapter 4.5 --- Functional Difference Between Wild-type and Mutant HBX Protein --- p.89 / Chapter Chapter 5 --- Conclusions and Directions for Further Studies / Chapter 5.1 --- Conclusions --- p.91 / Chapter 5.2 --- Directions for Further Studies --- p.92 / References --- p.93 / Appendix / Chapter A1 --- Recipes of Reagents Used in this Study --- p.109 / Chapter A2 --- Schematic Setup of Downward Capillary Transfer of DNA --- p.112 / Chapter A3 --- Circle Map of the pGEM®-T Cloning Vector and Construct of the HBx-pGEM®-T Plasmid --- p.113 / Chapter A4 --- Circle Map of the pEGFP-Nl Cloning Vector and Construct of the HBx-GFP Plasmid --- p.114

Hepatitis C virus (HCV) infection has become a global public health concern with over 130 million people chronically infected and over 350,000 deaths every year from HCV-related liver diseases. GB virus-B (GBV-B) infection in tamarins is a surrogate model for acute HCV infection. Whilst HCV infection commonly leads to chronicity, GBV-B is naturally cleared. To better understand this natural clearance, this project aimed to study the associated humoral immune response to GBV-B. Additionally, GBV-B-specific antibodies were produced with the aim of characterising the pathology of the virus. Previously, there was no available GBV-B neutralisation assay to identify antibodies in this animal model. Therefore, a GBV-B neutralisation assay, based on a method that is known to be successful for the closely-related HCV, was developed. This method involved producing pseudotyped retroviral particles (PV) expressing the GBV-B envelope that could infect a human hepatocarcinoma cell line. GBV-B PV production was confirmed by western blotting. Future studies can now test archived tamarin sera in this assay for the presence of neutralising antibodies. Neutralising antibodies found through this model could be epitope mapped, and incorporated into HCV vaccine design strategies. To study the pathology of GBV-B infection, GBV-B-specific antibodies were also produced using two techniques in parallel- classical hybridoma technology and ribosome display. Antibodies targeting the nucleocapsid core protein of GBV-B have been previously detected in tamarins and served as the target for production of GBV-B antibodies using both aforementioned technologies. GBV-B core-specific antibodies were successfully isolated using both technologies and can now be used in downstream techniques, such as immunohistochemistry, to characterise the pathology of GBV-B infection thereby further validating the use of the animal model.

Sofosbuvir is a uridine based nucleotide inhibitor of the hepatitis C viral (HCV) polymerase that is the backbone of many treatment regimens. In combination with drugs targeting other viral enzymes (including the poorly potent guanosine analogue ribavirin or highly potent inhibitors of viral NS5A or protease) most patients clear virus and resistance to sofosbuvir is rare, allowing effective retreatment with sofosbuvir. Patients with Genotype 3 HCV respond less well than other genotypes and response is reduced in those previously exposed to interferon. Here we show that patientderived virus from patients with Genotype 3 HCV who relapse to sofosbuvir-based therapies have a reduced sensitivity to SOF in an in-vitro phenotyping assay. Analysis of viral sequencing data revealed two distinct polymorphisms (A150V and K206E) in the HCV polymerase that are associated with treatment failure and in-vitro; they reduce sofosbuvir sensitivity against genotype 3 hepatitis C virions. However both polymorphisms modify the cellular response to type I interferon and in cells lacking response to interferon the impact on sofosbuvir sensitivity is minimal. The A150V polymorphism reduces the response to interferon 70 fold whereas the K206E substitution has minimal effects on interferon in isolation but in combination with A150V reduces the response 100 fold. Preliminary data indicates that the A150V polymorphism interferes with the late response to type I interferons enabling the virus to overcome the induction of interferon-stimulated genes. These data indicate a complex interaction between direct acting antiviral drugs and the innate antiviral response.

Um estudo de caso-controle para investigar a associação entre a hanseníase e infecção pelo vírus da hepatite B (VHB) foi conduzido no período de 1992/93, na cidade de Goiânia e municípios contíguos - Estado de Goiás. Avaliou-se, também, a distribuição espacial da hanseníase neste aglomerado urbano. Inicialmente, os indivíduos com suspeita clínica de hanseníase foram submetidos a exames baciloscópicos e histopatológicos, independentemente da rotina do Programa de Controle de Hanseníase. Do total de 855 pacientes recémdiagnosticados de hanseníase, 600 eram residentes em área urbana, e foram categorizados em casos multibacilares (31,3 por cento ), paucibacilares (51,8 por cento ) e prováveis (16,8 por cento ). Foi realizada análise descritiva desta casuística, havendo nítida predominância do sexo masculino na forma multibacilar de hanseníase. A distribuição espacial dos pacientes possibilitou, através da análise exploratória das taxas de detecção, discriminar estratos de risco intra-urbano. Para o estudo de caso-controle, 552 pacientes de hanseníase de 1 O a 70 anos foram incluídos. Os controles (N =552) foram selecionados de indivíduos com ausência de sinais e sintomas sugestivos de hanseníase oriundos da demanda espontânea de ambulatórios de 7 unidades de saúde, localizadas na região de procedência dos casos. Os participantes - casos e controles - foram entrevistados para avaliar fatores de risco para hanseníase e infecção pelo vírus da hepatite B. Foram coletadas amostras de sangue para detecção de marcadores ao vírus da hepatite B pela técnica de ELISA. Comparou-se a prevalência de marcadores de exposição (anti-HBc), de imunidade (anti-HBs) e de portador (AgHBs) entre casos e controles. Foram avaliados como potenciais fatores de confusão: sexo, idade, condições sócio-econômicas, estado nutricional, cicatriz vacinal de BCG e utilização dos serviços de saúde. Casos e controles foram similares quanto às características sócio-econômicas e nutricionais indicando que o princípio de selecionar controles da mesma base populacional que os casos parece ter sido adequado. Cicatriz vacinal de BCG esteve estatisticamente associada aos diferentes tipos de hanseníase. Houve maior proporção de indivíduos hospitalizados nos útimos 5 anos entre casos que em controles indicando que o emparelhamento por local de residência não eliminou completamente as diferenças entre os grupos em relação ao uso dos serviços de saúde. Entre os participantes do estudo, 18,1 por cento dos casos e 19,6 por cento dos controles foram soropositivos ao anti-HBc. Em análise multivariada, utilizando-se o modelo de regressão logística politômica, a associação da hanseníase e anti-HBc entre casos e controles apresentou odds ratio de 0,9 (IC95 por cento O, 7-1 ,3) para a categoria de multibacilar; 1,0 (IC 95 por cento 0,7-1,3) para a de paucibacilar e 1,1 (IC95 por cento 0,8-1,5) para a de provável. Estes resultados mostraram que subgrupos de casos e os controles estiveram igualmente expostos ao vírus da hepatite B. As proporções de indivíduos imunes foram semelhantes nos grupos de casos (9,2 por cento ) e controles (10,2 por cento ). Casos multibacilares responderam à exposição viral com formação de anticorpos protetores, qualitativa e quantitativamente de maneira semelhante aos pacientes paucibacilares e grupo controle. Os resultados dos índices de persistência de infecção (PPI) indicaram não haver diferença quanto ao clearance do antígeno viral nos subgrupos de casos e controles. Os resultados obtidos nesta investigação mostraram nos subgrupos de casos e controles: (i) prevalências semelhantes dos marcadores de exposição, de imunidade e de estado de portador; (ii) capacidade similar para produção de anticorpos protetores, avaliada através dos percentuais do marcador anti-HBs e, quantitativamente, através do Índice de Elisa e (iii) baixa probabilidade de persistência da antigenemia mensurada pelo PPI. Em conclusão, não houve evidências epidemiológicas de uma associação entre hanseníase e infecção pelo vírus da hepatite B, avaliada através de estudo de caso-controle, conduzido em área de baixa endemicidade ao VHB e alta endemicidade de hanseníase. / A case-control study was conducted in Goiânia, Central Brazil, a highly endemic area for leprosy and Iow endemic region for hepatitis B virus (HBV) infection. The purpose was to investigate the association between leprosy types and hepatitis B infection. The spatial distribution of leprosy in urban area was assessed. Between 1992 and 1993, newly detected leprosy cases (N=855) were investigated and 600 cases lived in the urban area. They were classified in multibacillary (31.3 per cent ), paucibacillary (51.8 per cent ) and probable cases (16.8 per cent ) according to histopathological and baciloscopic exams, independently of the leprosy control routine. The majority of multibacillary cases was males. Detection rates of leprosy were calculated by mapping cases and several risk strata were identified by using exploratory data analysis. This methodology seems to be particularly useful for targeting control activities in urban areas. Cases were 552 leprosy patients from the urban area and adjacent counties, between the ages of 1O and 70 years who self-referred or were referred to the main outpatient clinic for treatment in the region. 552 controls were selected from among self-referred outpatients from 7 health centers geographically located in areas where the cases came from. The main criteria for eligibility for control subjects was that they must not have any signs or symptoms indicative of leprosy. Blood samples were collected for all participants to determine serological markers of HBV infection and tested by enzyme immunoabsorbent assay technique (ELISA). Cases and controls were interviewed in order to evaluate risk factors for leprosy and hepatitis B vírus (HBV) infection. Prevalence of HBV exposure (anti-HBc), immunity (anti-HBs) and carrier status (AgHBs) were compared among cases and controls. Cases and controls were also compared for age, sex, socio-economic conditions, nutritional status, BCG scars and previous hospitalization. The participants had similar socio-economic pattern and also nutrition status, suggesting that the source of control selection was adequate for controlling for the most common confounding variables. BCG vaccine appeared to provide protection against multibacillary and paucibacillary types of leprosy and percentage of hospitalization was higher among cases. Prevalence of anti-HBc was similar among leprosy cases (18.1 per cent ) compared to controls (19.6 per cent ). An analysis of association between anti-HBc infection and leprosy types in terms of odds ratio, calculated by polytomous logistic regression, showed no positive association: multibacillary (OR=0.9 CI95 per cent 0.7-1.3); paucibacillary (OR= 1.0 CI95 per cent 0.7-1.3) and probable (OR= 1.1 CI95 per cent 0.8-1.5). The main findings of the case-control study were: (i) cases and controls had similar leveis of viral exposure, immune and carrier status (íi) the persistence of antigen response (PPI) was low among cases and controls respectively; (iii) ELISA índices were similar among multibacillary, paucibacillary and control group indicating that all participants mount antibody response to viral infection. In conclusion, there was no association between multibacillary leprosy and HBV infection in this setting.

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by Zhong Sheng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (p. 186-203). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.